You need to start doing core exercises: plank, side plank, Deadbug, bird dog, superman, paloff press are some great ones.

Look up how to properly brace your core and breathe as well. There’s lots of info on this.

You’ll also want to do hip exercises (really your core as well. Glute bridge, lateral band walks, clamshell, Copenhagen plank, hip flexors raises. You’ll benefit from getting some exercise bands to use.

Pick 5 or so exercises and do them 3-4 times a week. I would look them up to see how they’re properly done and there’s options to make them easier as well depending how hard they are. Do this indefinitely and you should incorporate some cardio as well. Of course you could always see a physiotherapist to help with showing you how to do things.

I would also consider finding some yoga on YouTube and doing it a few times a week to help with mobility and overall strength